VM instruction implementation without huge switch()?

How would one go about making a virtual machine without using a huge and clumsy switch( opcode ) statement?

The architecture I'm implementing (DCPU-16) has about 35-40 different instructions.

>>63

C99 increased that to 1023

Probably related to the compiler having to store a jump table with that much entries, not byte size.

C++ increased that [...] to 16K

That's just wasteful.
Remember that a C89 compiler can be implemented for a machine with like 1MiB of RAM (probably the biggest culprit: #defines: up to 1024*(499+31) bytes).

Polite sage for offtopic.